October 2012 Issue of Linux Journal: The Kernel

The Seats Are Bolted Down

One of my favorite Linux kernel analogies is that of an airplane losing
altitude. In the movies, when a plane suffers damage, the brave hero rips
off the door and starts throwing things out in order to lighten the load.
Suitcases fly, bags of peanuts scatter and anything not bolted down goes
out in order to save the passengers. When a computer system gets old, or is
low-powered to begin with, the Linux kernel can work the same way.
Computers are so powerful now, we don't often think about removing kernel
modules to gain speed, but not too many years ago, it was common to tweak
our systems by stripping out unneeded or unused drivers. We seldom turn to
our beloved kernel for speed increases anymore, but it's still the core of
our OS. Most users don't think about the kernel, but then again, Linux
Journal readers aren't most users. This month's issue is dedicated to the
kernel. If that scares you off, fear not, we cover lots of other topics
too.

Reuven M. Lerner starts off the issue with his take on switching to the Chrome
browser. Like Reuven, I've been a Firefox user since before it was cool.
About six months ago, I switched to Chrome too. This month, Reuven
discusses how the switch went for him.
Whether you're a Google fan, or think Google is horrible (or
both), Chrome is a popular and viable browser. Now you get to see
what a programmer thinks. Our other resident programmer, Dave Taylor,
tackles another interesting challenge. Can there be a template for a bash
script that is flexible enough to fill most needs, while providing a
standard framework to facilitate best practices? If you've ever written a
script knowing you should add more, but don't have the time to do it
"right", Dave's article is for you.

Kyle Rankin writes about methods for deploying servers this month. Oh sure, that
sounds like a basic tenant of system administration, but Kyle goes from
the standard "insert CD and boot" method all the way to centralized
configuration. If you're working in a corporate environment, chances are
you don't have time to install servers one by one, and even if you do
have time, it would be time wasted. Kyle's article might change the way
you think about server installation, and more important, it might change
the way you do it.

My contribution to the kernel issue is rather small. In fact, it will fit
in your pocket. In my Open-Source Classroom column, I discuss
the oft-confusing art of rooting an Android device. And, because rooting often
is followed by installing custom ROMs, I cover that too. If you've ever wanted
to try CyanogenMod on your phone, this month's article should be a big
help. If you have an iPhone, well, feel free to read about what all the
cool kids can do!

Javier Martinez Canillas starts off the nitty-gritty kernel articles with
an introduction to kbuild. Like any other open-source project, the Linux
kernel is the work of many people working together. Javier describes the
system and shows how to add to the kernel.
After reading an article on how to add to the kernel, I recommend a quick
followup with Igor Ljubuncic and Raphael Sack's article on dealing with
kernel crashes. An unstable kernel can go from bad to catastrophic quite
quickly, so Igor and Raphael discuss how to automate the identification and
handling of such events. Following their lead, hopefully your next kernel
panic won't mean sysadmin panic as well.

Matt Davis also helps us deal with system problems at a low level using
canaries. No, it's not just listening to their beautiful songs to soothe us.
Rather, just like the miners of old using canaries to detect problems in a
mine, a stack canary can detect system problems before any serious damage
happens. If building safeguards into your code sounds like a good idea, or
if you just want to read Matt's discussion of the Terminator Canary, you'll want to
check out his article.

We finish the issue with a topic near and dear to my heart. Darren
Douglas talks about teaching. I've been a professional Linux trainer for
several years now, and Darren really drives home some important points
regarding how we teach what we teach. Whether you're a trainer yourself
looking for a gut check, or just an avid user desiring to share your
knowledge with others, Darren really hits the target.

On the surface, this issue might sound intimidating to those folks who
usually steer clear of the kernel. Thankfully, we do the hard work of
tossing out the extra baggage so all you have left are those things bolted
down and worth reading. Plus, we have plenty of other things—product
announcements, tech tips and more—to keep you informed and
entertained. So have a seat, put your trays in the upright position and
enjoy this issue of Linux Journal.

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